The capillary column gas chromatography measures benzene in water-based epoxy coatings

China Coatings Online News Information Abstract: Water-based epoxy coatings are formulated from water-based epoxy resins and composite modified polyphosphonate resins and other auxiliary materials, in recent years, laws and regulations on environmental pollution restrictions have been issued, which involve the paint industry has VOC emission restrictions, because the traditional solvent-based coatings in VOC not only cause pollution to the environment, but also to the human body is extremely harmful, the state strictly restricts VOC emissions.
-based epoxy coating is made of water-based epoxy resin and composite modified polyphosphonamide resin and other auxiliary materials, without organic solvents. The content of benzene and toluene in water-based epoxy coatings was measured by the internal standard method, the percentage content of benzene was 0.17%, the RSD value was 0.60%, the recovery rate of the label was 99.23% to 99.41%, the percentage content of toluene was 0.29%, the RSD value was 0.42%, plus The standard recovery rate range is 99.63% to 99.82%, in line with GB/18581-2001 "current paint safety standards" of benzene, toluene content ≤0.3%, the standard recovery rate range of 98.0% to 102.0%, this coating in line with national standards. The method is simple, easy to operate, high sensitivity, good reproducible, can be popularized.
"keyword" water-based epoxy coating content determination capillary column gas chromatography using capillary column gas chromatography to determine the water-based epoxy coating benzene, toluene, the method is accurate, high recovery rate, good reproducible, high precision, and simple operation, is an economical and practical method. It provides a theoretical basis for quality control in the production of the coating.
1 experimental part 1.1 instrument, reagent Sp-6890 gas chromatography (column temperature: 180 degrees C; test room temperature: 170 degrees C; gas flow: 0.8mL/min).
gasification chamber temperature: 160 degrees C; air flow: 0.8mL/min); EL204 electronic balance; KQ-300DE-type CNC ultrasonic cleaner; internal object: isotrophol (analytical pure); calibration compounds: benzene, toluene (chromatography pure); thinner: ethyl ethylene, methanol (chromatography pure), positive propylene alcohol (pure spectrum);
2 experimental results and discussion of the best parameters of the 2.1 gas chromatography determine the column temperature of 170 degrees C, the peak of the chromatography expands and has a tail, the temperature is too low;
The temperature of the gasification chamber is 170 degrees C, compared with other spectral maps, the number of chromatography peaks has changed, the reproduction difference is poor, the temperature is too high, the gasification chamber temperature is 140 degrees C, the peak type is irregular, the temperature is too low, the gasification chamber temperature is 160 degrees C, the temperature of the chromatography, peak normal, the peak number remains the same, so the gasification chamber temperature is the best.
2.2 relative correction factor test results 2.2.1 benzene relative correction factor determination is called the quality of benzene 0.0207g, 0.0218g, 0.0213g, the mass of the internal object is 0.0219g, 0.0205g, 0.0217g, measured The peak area of benzene was 19815.945, 20103.109, 19772.144, and the peak area of the internal object was 19811.637, 17892.699, 18947.140, respectively, and the relative correction factor of benzene was 0.945.
of the relative correction factor of 2.2.2 toluene was called 0.0206g, 0.0220g, 0.0217g, and the mass of the internal object was 0.0219g, 0.0205g, 0.0217g, and the peak area of benzene was measured. At 18804.478, 19279.037, 18985.210, the peak area of the internal object was 19811.637, 17892.699, 18947.140, and the relative correction factor for toluene was 0.995.
0.16g/kg for benzene in samples with 2.3 mark-up recovery test results, 0.28g/kg for toluene, and 0.0122g for benzene. 0.0231g, 0.0326g, 0.0106g, 0.0210g, 0.0311g, plus After-standard benzene measurement values are 1.37g/k, 2.46g/kg, 3.40g/kg, toluene measurement values are 1.34g/kg, 2.37g/kg 3.38g/kg, the standard recovery rate of benzene was 99.23% to 99.41%, and the standard recovery rate of toluene was 99.63% to 99.82%.
2.4 internal standard test results show that the quality of the samples taken is 2.0081g, 1.9989g, 2.0119g, and the mass of the internal targets is 0.0216g and 0.0216g, respectively. 0.0207g, 0.0231g, the peak area of benzene is 2674.981, 2616.509, 2961.351, toluene peak area is 4511.419, 4330.195, 4876.178, the peak area of the inner object is 16479.233, 15332.637, In 19107.531, the average percentage content of benzene was 0.166%, RSD was 0.62%, toluene was 0.292% and RSD was 0.42%.
3 Conclusion Capillary column gas chromatography to determine the content of benzene and toluene in water-based epoxy coatings, simple operation, precision, high accuracy, by consulting GB/18581-2001 "current paint safety standards" in the provisions of benzene and toluene content limits, this product meets the paint safety standards. The method meets the measurement requirements and is suitable for popularization. Responsible Editor: Wang Cairu